1. Field of the Invention
The present invention relates to a document feeder and an image forming apparatus provided with the document feeder. In particular, the present invention relates to document feeding control when transporting the document to a reading position.
2. Related Background Art
Documents are automatically fed to a predetermined reading position on a platen glass plate in conventional image forming apparatuses such as digital copying machines, printers, and facsimiles, and therefore an auto document feeder, which is a document feeder, is provided on the apparatus main body so as to be openable and closable. Reading of an image is then performed by using an exposure portion with respect to the document that is thus automatically transported by the auto document feeder.
Here, a method of reading an image by fixing an exposure apparatus below the predetermined reading position of the platen glass plate, and moving the document over the exposure apparatus at a fixed speed (hereinafter referred to as flow reading) is conventionally known as this type of method of reading a document image.
If this type of flow reading is performed with a conventional auto document feeder, a document is transported to the reading position after determining whether or not the exposure apparatus is capable of reading. The document is therefore stopped temporarily at an initial feed position as a standby position before the document is transported to the reading position, regardless of whether or not the exposure apparatus is capable of reading. It is then verified that image reading is allowed, and thereafter the document is transported to the reading position.
However, the document must be temporarily stopped at the initial feed position with the above-mentioned structure, regardless of the fact that image reading is possible, and therefore the number of sheets processed becomes less. Further, there is an inconvenience in that document transport operation is not stable because the document being transported is temporarily stopped, and then again transported.